User guide

Appendix B - License File Format
License File Syntax
108 FLEXnet Licensing End User Guide
Example:
SERVER my_server 17007ea8 21987
Three-Server Redundant Configurations
The machines that compose a three-server redundant configuration are required to have
excellent communications. This form of redundancy requires that the servers exchange
heartbeats periodically, and poor communications can cause poor performance. Avoid
configuring redundant servers with slow communications or dial-up links.
Maintain an identical copy of the license file (as well as the
lmgrd and the vendor daemons
binaries) locally on each server machine rather than on a file server. If you do not do this, you
lose all the advantages of having redundant servers, since the file server holding these files
becomes a single point of failure.
Three-server redundant configurations are specified by including three SERVER lines in the
license file. The set of three SERVER lines must appear in the same order with each line for a
given server being identical across all three files. At any given moment in time,
lmgrd has a
notion of the master server, whose duties include:
• Serving licenses
• Recording information into the debug log
• Recording usage information into the report log
By default the primary server is the master; the method of transitioning the master server duties,
in case of primary server failure, is controlled by the PRIMARY_IS_MASTER parameter.
Why are three license server systems required in a redundant configura-
tion?
In order to provide for license server system failover, multiple redundant server systems, each
running on their own machine, must be able to serve the same set of counted licenses. However,
to ensure consistency and security of the software publisher’s licenses, these redundant license
server systems must ensure that only one of them can serve licenses at any one time.
A given set of counted licenses is bound to the hostids of a specific number of redundant license
server machines via SERVER lines in the license file. In this way, each license server system
knows how to communicate with the other redundant license server systems that are bound to
the same set of counted licenses. Upon startup, each server system determines whether or not it
can communicate with the other redundant license server systems. A group of redundant license
server systems is formed when all members of the group can each communicate with all others
in that same group.
Once a group is formed, the group guarantees that only one of its license servers can serve
licenses at any one time. However, FLEXnet Licensing must ensure that only one such group
will be formed from the total number of redundant license servers. To ensure that there is only
one group that is formed, only the group that contains greater than one half of the redundant
license servers allows itself to serve licenses. This group of license servers is called the